<!DOCTYPE html>
<html class="reftest-wait">
<title>Transform animation whose target is not initially associated with any document creates a stacking context even if it has only 'transform:none' in its keyframe</title>
<style>
span {
  height: 100px;
  width: 100px;
  position: fixed;
  background: green;
  top: 50px;
}
div {
  width: 100px; height: 100px;
  background: blue;
}
</style>
<span></span>
<script>
  var div = document.createElement("div")
  var anim = div.animate({ transform: ['none', 'none'] },
                         { duration: 100000 });
  document.body.appendChild(div);
  anim.ready.then(function() {
    document.documentElement.classList.remove("reftest-wait");
  });
</script>
